Hitachi Medical Corporation

Hitachi, Ltd.

Other

Mitsubishi Denki Kabushiki Kaisha

Sumitomo Special Metals Co., Ltd.

Hitachi Engineering Co., Ltd.

Hirotaka Takeshima

Hajime Kawano

Takeshi Yatsuo

Shigeru Kakugawa

Takao Honmei

Yoshihide Wadayama

Hiroyuki Takeuchi

Kenji Sakakibara

Hiroyuki Watanabe

Noriaki Hino

Hiroshi Tazaki

Hajime Tanabe

Mitsushi Abe

Tsutomu Yamamoto

Shigenori Kuroda

Nobuhiro Hara

Takao Hommei

Akiyoshi Komura

Shigeru Watanabe

Akira Kurome

Yutaka Takuma

Chikako Nakamura

Shouji Kitamura

Takayuki Abe

Tetsuhiko Takahashi

Munetaka Tsuda

Tsuyoshi Wakuda

Masaaki Aoki

Yoshiyuki Miyamoto

Ryozo Takeuchi

Katsunori Azuma

Hiroshi Morita

Shigeru Sato

Naoki Maki

Yasuyuki Tahara

Kazuki Moritsu

Hideya Sakurai

Tomoo Chiba

Shigeki Tounosu

Hirofumi Motoshiromizu

Kunihito Suzuki

Hiromichi Shimizu

Yasuhiro Marukawa

Munenori Kotabe

Junji Uzuki

Kiyoshi Fukutomi

Takashi Yamamizu

Kimiharu Ota

Shichihei Sakuragi

An electromagnet device which generates magnetic field in the direction perpendicular to the inserting direction of an inspection subject is reduced in size and weight by removing unnecessary arrangement as much as possible. A magnetic resonance imaging device is also provided. The electromagnet device comprises a first coil () through which a first circular current (J) circulates forward, a second coil () through which a second circular current (J) circulates reversely, and a coil group () through which a plurality of circular currents (J-J) circulate alternately forward and reversely. The first coil (), the second coil () and the coil group () are arranged in this order to increase the angle of elevation &#x3b8; (&#x3b8;1&#x3c;&#x3b8;2&#x3c;&#x3b8;3), and a blank region (S) not including the second coil () and the coil group () exists in the angular region between the angles of elevation &#x3b8;2 and &#x3b8;3.

Electromagnet devices compatible with magnetic resonance and MRI devices where circulating current directions alternate between coil groups separated by elevation angles between 26.25 and 55 degrees

A coil pattern calculation method includes calculating a current potential at each contact between finite surface elements forming each of the coil surfaces based on an initial value of an input current potential distribution, and, for each of the coil surfaces, repeatedly calculating the current potential alternately and, under each magnetic field condition, determining a current potential distribution that generates a magnetic field falling within the range of allowable error for each target magnetic field so that a surface current represented by the current potential will become close to a target magnetic field distribution set for each of the finite surface elements; and determining a coil pattern from the contour lines of the determined current potential distribution.

Method of calculating coil pattern, and gradient magnetic field coil

In a superconducting magnet, including a vacuum vessel, a coil vessel inside the vacuum vessel, and a superconducting coil inside the coil vessel for generating a magnetic field, has a magnetic member, disposed inside the vacuum vessel, supported with thermal insulation, for compensating the magnetic field; a heat exchange device disposed outside the vacuum vessel for supplying to or absorbing heat from the vacuum vessel; and thermal conducting members thermally connecting the heat exchange device via the vacuum vessel to the magnetic member. An MRI including the superconducting magnet is also disclosed.

Superconducting magnet and magnetic resonance imaging apparatus

A magnetic resonance imaging apparatus capable of suppressing noise caused by vibration of a gradient magnetic field coil and improving image quality includes a large number of ferromagnetic shims disposed in a large number of holes formed in a shim tray, and vibration dampers disposed in holes formed in the shim tray to reduce noise generated by vibration of a gradient magnetic field generating coil.

Magnetic resonance imaging apparatus with noise suppressing structure

A magnetic resonance imaging apparatus is provide that includes static magnetic field generation means arranged around an imaging space where an examinee is to be located and generating a static magnetic field in the imaging space; gradient magnetic field generation means arranged in the imaging space side of the static magnetic field generation means and generating a gradient magnetic field in the imaging space; and high-frequency magnetic field generation means arranged at the imaging space side of the gradient magnetic field generation means and generating a high-frequency magnetic field in the imaging space. The gradient magnetic field generation means has a concave portion in the vicinity of the imaging space depressed toward the static magnetic field generation means. At least a part of the high-frequency magnetic field generation means is contained in the concave portion.

Magnetic resonance imaging apparatus

An MRI apparatus having a configuration that reduces vibration of a static magnetic field generating source is provided. A closed vesselof the static magnetic field generating source is provided with a rigid structurefor preventing transmission of vibration generated from a gradient magnetic field generating partto other members via the closed vessel. The rigid structureuses, for example, a connecting partthat connects a faceon the imaging space side and a faceconfronting it. The rigidity of the closed vessel is thereby increased, and therefore vibration transmitted from the gradient magnetic field generating part can be reduced. The connecting part can have a through-hole structure, and in such a case, internal space of through-hole can be used for drawing cables.

Magnetic resonance imaging device

A gradient coil apparatus for magnetic resonance imaging system includes a plurality of gradient coilsandfor applying a gradient magnetic field to a test object and an internal heat exchangerto be immersed in insulation oilin a container. A pumpis disposed to circulate coolant between the internal heat exchangerand an external heat exchangeris disposed outside of the container. This arrangement allows the insulation oil only inside of the container, thereby ensuring a substantial reduction in the amount of insulation oil.

Gradient coil apparatus for magnetic resonance imaging system

In a measuring space of the object (), an essential measurement region () having a center region of the measuring space and a plurality of peripheral measurement regions () which do not have any region overlapped with the essential measurement region are set. Then, the essential measurement region is combined with a selected peripheral portion of the plurality of the peripheral measurement regions to measure in a preceding manner a nuclear magnetic resonance signal from the object as data of the measuring space. The essential measurement region is combined with the peripheral measurement region of the plurality of the peripheral measurement regions which has not been selected in the preceding measuring step to measure a nuclear magnetic resonance signal from the object as data of the measuring space. Sequentially, the essential measurement region is combined with the peripheral measurement region having not been measured in a preceding measuring step to measure a nuclear magnetic resonance signal from the object. The data of the essential measurement region and the data of the peripheral measurement region thus measured is supplemented with the data of the peripheral measurement region measured in the preceding measuring step to generate data of the measuring space.

Measuring method in magnetic resonance imaging device and magnetic resonance imaging device

The present invention is intended to provide a magnetic pole, a magnet apparatus, and a magnetic resonance imaging apparatus that the magnetic structure of the magnet apparatus for generating a uniform magnetic field is formed in a lower burst mode, and the profitability is increased, and at the same time, the uniformity of the magnetic field is improved. According to the present invention, the magnetic poles arranged opposite to each other across a measuring space have at least one of a plurality of hollows and a single hollow having a shape continuously changing on the section perpendicular to the direction of the magnetic field formed in the measuring space and particularly in order to make the magnetic field uniform, the arrangement of the plurality of hollows and the shape of the single hollow are adjusted. The magnet apparatus and magnetic resonance imaging apparatus of the present invention are structured as mentioned above.

Magnetic pole magnet device using the magnetic pole, and magnetic resonance imaging apparatus

To reduce vibration and noise generated in supplying pulsatile current to the gradient magnetic field coil for driving that coil in a MRI apparatus, an active shielded gradient magnetic field coil is used, in which the gradient magnetic field coil is supported by and fixed to the static magnetic field generating magnet. The supporter for supporting this gradient magnetic field coil in non-contact does not prevent the interventional procedure performed by a doctor. Further, an eddy current generated on the surface of the static magnetic field generating magnet near the periphery of the gradient magnetic field coil, when supplying the pulsatile current to the gradient magnetic field coil, can be reduced.

Magnetic resonance imaging device and gradient magnetic field coil used for it

A magnet device provided with a shield current carrying means in which two sets of magneto-static field generating sources for generating magnetic fields directed towards a first direction are disposed facing each other across a finite region and at least one set of the magneto-static field generating sources are disclosed on at least two almost concentric circles. A first plane includes a first axis, a second axis and a first point. The first point is a point of insertion between the first axis parallel to the first direction and passing almost through the center of the shield current carrying means. The second axis crosses at right angles to the first axis and is spaced almost equal distance from the two sets of the generating sources. The alternately arranged positive and negative current carrying directions of the shield current carrying means are set in the order of increasing value of &#x3b8;n.

Low-leakage magnetic-field magnet and shield coil assembly

A magnetic resonance imaging apparatus is provided with a sequencer for executing a rapid imaging sequence of up to 100 ms at a full scan, a parallel measurement system for executing a partial encoding measurement in which the number of phase encoding operations performed for the measurement is reduced, an image processing system for reconstructing images from the information obtained though parallel measurements and composing reconstructed images of a plurality of areas to make one image, a display system for displaying the obtained images at a rate of 50 frame/second or more, and an image renewal system for taking in coordinate information of the cross-section to be imaged from position and pointing devices at intervals of about 0.1 second, and renewing the cross-section to be imaged in real time. Thus, imaging on the cross-sections indicated by a device can be performed in real time with high spatial and high time resolution.

Magnetic resonance imaging system

An open-type magnet device for MRI includes a pair of upper and lower magnet assemblies, and shims are provided on opposite sides of their cooling containers and/or in holes passing through central portions of the cooling containers so as to facilitate providing a highly homogeneous static magnetic field.

Open-type magnet device for MRI

A magnet device includes two sets of static magnetic field generation sources spaced from each other in the vertical direction such that the uniform magnetic field region (patient space) is between then. Each set has concentric current carrying coils to generate a uniform magnetic field in a first direction (the vertical direction). Several such coils are used in each set, disposed such that when a first axis which is parallel to the first (vertical) direction and passes substantially through the centers of the current carrying coils crosses, at a first point, a second axis which is orthogonal to the first axis and is at substantially equal distance from the respective static magnetic field generation sources, the current carrying coils are disposed in such a manner that when geometrical centers of cross sections of the current carrying coils are projected on a first straight line that is in a first plane containing the first axis, the second axis and the first point and passing through the first point, the directions of the currents of the carrying coils at the respective corresponding projections align alternatively in positive and negative directions on the first straight line.

Magnet apparatus and mri apparatus

Growing community of inventors

Ryugasaki, Japan

Hirotaka Takeshima